If you're looking for an ideal location of accommodation in Chiang Mai, staying in the Old City or nearby the historic center is your best bet. During our last visit in Chiang Mai we decided to stay in a calm corner just outside the Old City, at Si Phum Heritage Boutique Bed & Breakfast. Check for our review of the hotel.
There is a wide range of accommodation in Sapa and the area around Sapa town is a great choice to stay when exploring all major highlights of the mountainous town and its surroundings. During our last visit we decided to stay at Sapa Scenery Hotel for 2 nights of our trip. Our review of the hotel in Sapa.